Date/time support
Date/time support has been fully rewritten in PHP 5.1.x, and no longer uses the system settings to 'know' the timezone in operation. It will instead utilize, in the following order:
- 
    The timezone set using the date_default_timezone_set() function (if any) 
- 
    The TZ environment variable (if non empty) 
- 
    "magical" guess (if the operating system supports it) 
- 
    If none of the above options succeeds, UTC 
To ensure accuracy (and avoid an E_STRICT warning), you will need to define your timezone in your php.ini using the following format:
date.timezone = Europe/London
The supported timezones are listed, in this format, in the timezones appendix.
Also note that strtotime() now returns FALSE on failure, instead of -1.